This invention relates generally to the field of determining drugs of abuse in biological samples. More specifically, it provides a system of derivatives, conjugates and specific antibodies which may be used in assay systems for detection or quantitation of 3,4-methylenedioxymethamphetamine (MDMA), also known as ecstasy, and other related compounds.
Designer drugs are specific derivatives of commonly encountered drugs of abuse which are popular within some geographic regions and populations. Use of designer drugs carries all of the risks involved in use of more common drugs, as well as additional risks, in that detection and subsequent treatment is complicated by designer drugs' relative uniqueness. For example, some emergency facilities may not be able to detect designer drugs because such facilities lack the sophisticated and expensive instrumentation, such as gas chromatography/mass spectroscopy (GC/MS) equipment, used in confirming a positive result. Rapid screening methods such as immunoassays are more widely available, easy to use, and economical, but commonly detect only a single one of, or at most, a limited number of, the most commonly encountered drugs. Thus, they are not specific for a larger class of designer drugs.
One such class of designer drugs is the ecstasy class. Non-limiting examples of compounds in this class include, 3,4-methylenedioxymethamphetamine (MDMA), also known as “ecstasy”, 3,4-methylenedioxyamphetamine (MDA), N-ethyl-3,4-methylenedioxyamphetamine (MDE) N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB), 1-(3,4-methylenedioxyphenyl)-2-butanamine (BDB) and other derivatives of amphetamine. In fact, as drug designers develop more and more variants of ecstasy, the number of unique compounds which falls within the ecstasy class continues to grow.
Detection of MDMA, MDA, MDE, MBDB, BDB, another ecstasy-class compound, or a derivative or metabolite thereof, in the urine currently depends upon cross-reactivity of such ecstasy-class drugs in immunoassays for amphetamine and methamphetamine. These assays, however, fail to detect such ecstasy-class compounds at lower concentrations. Moreover, existing immunoassays for amphetamine and methamphetamine are limited by their cross-reactivity to over-the-counter allergy and cold medications, such as (±) ephedrine, (+) pseudoephedrine, and phenylpropanolamine, and to prescription diet drugs such as phentermine. This cross-reactivity factor prevents one from lowering the cut-off level for detection of amphetamine and methamphetamine, which, in turn, prevents detecting ecstasy-class compounds at lower concentrations. Therefore, an assay with increased specificity for ecstasy-class compounds is needed, either as an assay to detect ecstasy-class compounds alone, or as an assay to detect ecstasy-class compounds as well as amphetamine and methamphetamine.